MONTPELIER — The Vermont Agency of Transportation says a section of rock ledge on Interstate 89 has become unstable and that the agency will be issuing a revised schedule to remove the rock near the Richmond-Bolton town line.

Until then, the agency has closed the passing lane on the southbound side of the interstate.

The agency said continuing fickle weather patterns have combined with contractor scheduling issues to delay the beginning of work to remove the loose rocks. The agency said it hopes work can get started later this week.